Fluid mixing is vital to most production systems in the chemical process and allied industries. It has extreme importance in the mining, food petroleum, chemicals, pharmaceuticals, pulp and paper, and power industries, and in municipal and industrial waste treatment facilities.
In an axial-flow mixing impeller a flow is generated parallel to the mixing impeller shaft, along the impeller axis. Axial-flow impellers generally generate more fluid flow per horsepower than radial impellers.
A significant drawback resulting from the use of a conventional mixing impeller is the low efficiencies of the device when run at higher speeds to decrease mixing time. A general value for efficiency may be between 0.3% to 1.1%, while at lower speeds may increase to as high as 7.0%. This efficiency value is a reflection of how much power is consumed per unit of volume mixed. The less power consumed to mix a given volume of fluid, the more efficient the device.
Two of the most significant factors that affect the overall efficiency of a mixing device is the production of a strong, purging circulatory flow within a mixing reservoir and the pressure differential between the back and the face of the blade which on a conventional impeller have a foil-like construction rotated in a narrow plane resulting in very significant pressure differentials between the face and the back of the blade.